3个柔性加工机器来加工3个工件;工件一有三道工序,在三个机器上的加工时间分别为2 4 3;工件二有三道工序,在三个机器上的加工时间分别为5 7 6;工件三有三道工序,在三个机器上的加工时间分别为3 4 2,在Matlab用遗传算法进行编码,;
时间: 2024-03-15 17:44:19 浏览: 52
最小化含有柔性工序的双机流水工件加工时间研究
这个问题可以用遗传算法来求解,以下是MATLAB代码实现:
```matlab
% 定义工件和机器的数量
num_jobs = 3;
num_machines = 3;
% 定义各工件在各机器上的加工时间
processing_times = [
2 4 3;
5 7 6;
3 4 2;
];
% 定义遗传算法的参数
population_size = 50; % 种群大小
chromosome_length = num_jobs * num_machines; % 染色体长度
generations = 100; % 迭代次数
mutation_rate = 0.05; % 变异率
% 初始化种群
population = randi([0, 1], population_size, chromosome_length);
% 定义适应度函数
fitness_function = @(chromosome) schedule_fitness(chromosome, processing_times, num_jobs, num_machines);
% 迭代进化
for generation = 1:generations
% 计算种群适应度
fitness_values = zeros(1, population_size);
for i = 1:population_size
fitness_values(i) = fitness_function(population(i, :));
end
% 选择交叉配对的染色体
selected_chromosomes = zeros(population_size, chromosome_length);
for i = 1:population_size
chromosome1 = population(randi(population_size), :);
chromosome2 = population(randi(population_size), :);
if fitness_function(chromosome1) > fitness_function(chromosome2)
selected_chromosomes(i, :) = chromosome1;
else
selected_chromosomes(i, :) = chromosome2;
end
end
% 交叉配对
new_population = zeros(population_size, chromosome_length);
for i = 1:population_size
chromosome1 = selected_chromosomes(randi(population_size), :);
chromosome2 = selected_chromosomes(randi(population_size), :);
crossover_point = randi(chromosome_length - 1) + 1;
new_chromosome = [chromosome1(1:crossover_point), chromosome2(crossover_point+1:end)];
new_population(i, :) = new_chromosome;
end
% 变异
for i = 1:population_size
for j = 1:chromosome_length
if rand() < mutation_rate
new_population(i, j) = 1 - new_population(i, j);
end
end
end
% 更新种群
population = new_population;
end
% 选出最优解
best_chromosome = population(1, :);
best_fitness = fitness_function(best_chromosome);
for i = 2:population_size
fitness = fitness_function(population(i, :));
if fitness > best_fitness
best_chromosome = population(i, :);
best_fitness = fitness;
end
end
% 打印最优解和最优解的适应度
disp(best_chromosome);
disp(best_fitness);
% 定义适应度函数
function fitness = schedule_fitness(chromosome, processing_times, num_jobs, num_machines)
% 解码染色体
schedule = reshape(chromosome, num_jobs, num_machines);
% 计算每个工件的完成时间
completion_times = zeros(num_jobs, num_machines);
for j = 1:num_jobs
for m = 1:num_machines
if m == 1
completion_times(j, m) = processing_times(j, m) * schedule(j, m);
else
completion_times(j, m) = completion_times(j, m-1) + processing_times(j, m) * schedule(j, m);
end
end
end
% 计算每个工件的总加工时间
total_processing_times = max(completion_times, [], 2);
% 计算适应度
fitness = -sum(total_processing_times);
end
```
上面的代码中,首先定义了工件和机器的数量,以及各工件在各机器上的加工时间。然后定义了遗传算法的参数,包括种群大小、染色体长度、迭代次数和变异率。接着初始化种群,并定义了适应度函数。在迭代进化中,先计算种群适应度,然后选择交叉配对的染色体,进行交叉配对和变异,最后更新种群。在整个遗传算法的过程中,最重要的是适应度函数,它用于评估染色体的适应度。在这个问题中,适应度函数计算了每个工件的完成时间,然后计算了每个工件的总加工时间,最后返回其相反数作为适应度,这是因为在遗传算法中,适应度越大,表示该染色体的适应度越好。
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